The present invention relates to a method for simulating a joint which undergoes shear, tensile and/or compression strain due to stresses placed upon that joint. More specifically, the present invention relates to a method for simulating an adhesive joint which has an elasticity modulus which substantially changes over a period of time and/or over a range of temperatures.
Adhesive joints (e.g., joints formed from glues, adhesives or polymers) are used in a variety of applications to attach, connect and/or integrate components of articles of manufacture. Often it is desirable to model and/or simulate adhesive joints. Particularly, it is desirable to simulate an adhesive joint in order to gain a better knowledge of the strain a particular adhesive joint will experience when that particular joint is subjected to stress caused by forces placed upon the joint. This knowledge, amongst other things, aids and/or assists individuals in choosing whether a particular adhesive joint should be used for a particular article of manufacture where the article of manufacture subjects or exposes the joint to particular forces and/or stresses.
Conventional methods of simulating joints and simulating the strain experienced by such joints utilize conventional engineering equations which include elasticity moduli which relate the strain of a particular joint to the stress experienced by the joint. These conventional methods of simulating joints suffer from drawbacks. Conventional methods typically assume that an elasticity modulus for a particular joint is constant or substantially constant such that stress and strain have a substantially linear relationship.
In many instances, and particularly for adhesive joints which are drying or solidifying, the elasticity modulus of a particular adhesive joint changes substantially over time and at different temperatures. For example an adhesive joint which has recently been formed will become more resistant to strain as the joint solidifies, thereby changing the elasticity modulus of the joint over a period of time during which the adhesive is solidifying. Consequently, a conventional simulation of a joint which includes a constant elasticity modulus will inherently be inaccurate.
Therefore, it is desirable to provide a method of simulating an adhesive joint which includes an elastic modulus which changes as a function of time and/or temperature.
It is a first object of the present invention to provide a method for simulating an adhesive joint which overcomes the previously delineated drawbacks of conventional methods for simulating a joint.
It is a second object of the present invention to provide a method for simulating an adhesive joint which includes a modulus of elasticity which changes as a function of time and/or temperature.
According to a first aspect of the present invention a method for modeling an adhesive joint is disclosed, the joint having an elastic modulus which changes over a period of time. The method includes the steps of: collecting stress and strain values for the joint over the period of time; determining an elastic modulus for the joint as a function of time based upon the stress and strain values; and forming a simulated joint based upon the joint, the simulated joint capable of receiving simulated stress values and capable of producing strain values by using the elastic modulus.
According to a second aspect of the invention a method for modeling an adhesive joint, the adhesive joint having an elastic modulus which changes over a particular range of temperatures, said method comprising: collecting stress and strain values for the adhesive joint over the range of temperatures; determining an elastic modulus for the adhesive joint as a function of temperature based upon the stress and strain values; and forming a simulated joint based upon the adhesive joint, the simulated joint capable of receiving simulated stress values and capable of producing strain values by using the elastic modulus.
According to a third aspect of the invention a method for modeling an adhesive joint, the adhesive joint having an elastic modulus which changes over a particular period of time and over a range of temperatures, said method comprising: collecting stress and strain values for the adhesive joint over the period of time and said range of temperatures; determining an elastic modulus for the adhesive joint as a function of time and temperature based upon the stress and strain values; and forming a simulated joint based upon the adhesive joint, the simulated joint capable of receiving simulated stress values and capable of producing strain values by using the elastic modulus.
These and other objects, aspects, and advantages of the present invention will become apparent upon reading the following detailed description in combination with the accompanying drawings.